Fast product development with virtual prototyping and HiL-testing

In many industries virtual prototyping and Hardware-in-the-Loop (HiL) testing are a standard part of the product and control development processes. Using simulation models to design the product and to test controllers ensures performance and reliability.

The basis for this approach is system simulation: The technical system is reproduced in a mathematical model to predict its behavior on the computer. In this way, it is possible to identify problems at an early stage and to carry out extensive variant studies.
In contrast to detailed fluid dynamics simulation (CFD) or thermal analysis in solids (FEM), system simulation uses coarser spatial resolutions. The focus is on the interactions between different system components and physical effects. Both steady-state and dynamic problems can be investigated. Widely used tools for system simulation are Simulink and Dymola, although there are many other tools. The main benefits of system simulation and virtual prototyping are:
- Problem identification: Products can be tested virtually. This helps to detect errors even before prototypes are built.
- Design optimization: Individual simulations calculate in minutes. A large number of variants can be calculated and evaluated in a short time.
- Efficient development: Integrated into the development process, system simulation replaces part of the test bench experiments. This saves time as well as the budget. When it comes to control development, the first step is Model-in-the-Loop (MiL) testing. The control algorithms are embedded in a model and tested on the virtual prototype.
The next step is Software-in-the-Loop (SiL): the control unit code for the intended hardware is generated and tested on the product model. Finally, the real hardware controller is tested in a HiL setup. These technologies are very mature and established for electrical and mechanical applications, not so much for thermal applications such as heat pumps or refrigeration systems. But during the last years we had quite a few projects on HiL testing of thermal systems. Crucial ingredients for HiL tests are simulation models of the thermal system, that are accurate, fast and robust. We developed these models for our customers using our Modelica library TIL and set up a reliable tool chain to export these models to dedicated real time platforms.
Our toolchain from virtual prototyping to HiL tests allows for efficient product design and saves a considerable amount of expensive lab experiments.